Refrigerating apparatus



Oct. 26, 1943- R. E. GOULD ET AL REFRIGERATING APPARATUS Filed 001;. 29,1940 INVENTOR.

Patented Oct. 26, 1943 UNlTED STATES PATENT OFFICE BEFRIGERATINGAPPARATUS Richard E. Gould, Oakwood, and Charles F. Henney, Dayton,Ohio, assignors to General Motors Corporation, Dayton, Ohio, acorporationof Delaware Application October 29, 1940, Serial No. 363,317

= means for cooling and lubricating the compressor when no refrigerationis supplied to the evaporator.

Another object of this invention i to provide improved means forby-passing the main evaporator when no refrigeration is required.

Still another'object of this invention is to provide means for improvingthe efliciency of the refrigerating apparatus.

Further objects and advantages of. the present invention will beapparent from the following description, reference being had to theaccompanying drawing, wherein a preferred form of th 'present inventionis clearly shown.

In the drawing: v

The drawing diagrammatically shows our invention' as applied to arefrigerating system.

As disclosed in the drawing, the reference numeral l designates an airduct or a cabinet through which air to be conditioned is circulated.Reference numeral '2 designates an evaporator mounted in the pathof theair flowing. through the duct l. The air is circulated by means of a fanunit 3, which may be energized from any suitable source of electricalenergy (not shown). The reference numeral 4 designates a conventionalrotary compressor which discharges compressed refrigerant into thecasing I! from whence the compressed refrigerant enters the line 5 whichleads to the inner passage 6 of the heat interchanger 1. The refrigerantleaving the inner passage 6 is conveyed to the condenser 8.

through the line 9. The compressed refrigerant is condensed within thecondenser 8 and. thereafter flows into a conventional receiver l0.Liquid refrigerant from the receiver to is circulated through thecompressor cooling cham ber H.v

As shown in the drawing, the compressor casing comprises two sections l4and H which are secured together by means of the cap screws IS. The endwall I3 of the compressorv 4 separates the interior of the easing intotwo separate chambars. The chamber ll surrounds th main com- 7 Claims.(Cl. 62-115) pressor shaft bearing [2 which may be formed integrallywith the end wall 13 whereby the liquid refrigerant entering the chamberII serves to cool the mainbearing l2 and also serves to cool thecompressor mechanism through the wall i3. A shaft seal i5, ofconventional construction,

is provided at the point where the main shaft l6 passes through thecasing I4. By virtue of the location of the shaft seal IS, the shaftseal is also kept cool by the refrigerant flowing through the chamberll.

Inasmuch as a portion of the liquid refrigerant entering the chamber maybe converted into vapor by the heat generated by the compressormechanism and the shaft seal, the refrigerant leaving the chamber ll. iscaused to discharge into the outer chamber '20 of-the heat interchangerl8. As will be pointed out hereinafter, the relatively cold refrigerantvapor leaving the evaporator 2 flows through the inner passage 22 of theheat interchanger l8 whereby the refrigerant vapor enteringthe' outerchamber 2!] is recondensed before leaving the chamber 20. The outerchamber is provided with two cutlets. A first outlet 23 leads to themain evaporator 2. A second outlet 24 leads to the outer chamber-25 ofthe heat interchanger 1. The flow of refrigerant from the chamber 20 tothe evaporator 2 is controlled by a valve 26 which in turn 'iscontrolled by the thermostat 2'! which may be located either in thereturn air stream, as shown, or in the conditioned space. The valve 26is adapted to be closed whenever the thermostat 21 indicates that theair flowing through the duct I .does' not require further cooling; Inaddition to the valve 26, a conventional thermostatic expansion valve 28is provided for controlling the flow of liquid refrigerant to theevaporator .2 whenever cooling is required. The thermostatic expansionvalve 28 is of conventional construction and includes the usualthermostatic element 29 placed adjacent the outlet of th evaporator forclosing the valve 28 whenever the liquid refrigerant reaches theevaporator outlet.

The flow of refrigerant from the chamber 20 to the chamber 25 iscontrolled by a conventional expansion valve 30 which is set to open ata much lower pressure than the valve 28. The calibra tion of the valves.28 and 30 is such that sub-.- stantially all of the refrigerant flowsthrough the evaporator 2| at all times when refrigeration is requiredand the only time that the valve 30 is open is when one or both of thevalves 25 and 28 are closed. Upon opening of the valve 30, in respouseto a subnormal suction pressure, a prederefrigerant gas flowing throughthe inner chamher 6 of the heat interchanger I. The refrigerantvaporized in the chamber 25 is conveyed through the passage 3! to theinlet 32, of the chamber 22. Inasmuch as the refrigerant vapor flowingthrough the passage 3| will be relatively cool, it will serve tocondense any refrigerant vapor which may enter the chamber 20.

One purpose of providing the interchanger i8 is to make sure that all ofth refrigerant flowing either to the expansion valve 28, or to theexpansion valve 30, is in liquid form so that the valves will operateproperly. It has been found that valves of this type do not operateproperly when refrigerant vapor is mixed with the refrigerant suppliedto the valves.

By virtue of'the above described arrangement it is apparent that thesystem will cause a certain amount of refrigerant to be circulated by thcompressor at all times even though hr. refrigerant is supplied to theevaporator 2. Inasmuch as it is frequently desirable to operate thecompressor continuously, it is important that a certain minimum amountof refrigerant be circulated at all times so as to provide a constantsupply of liquid refrigerant for cooling the compressor. The amount ofrefrigerant passed by be circulated by the compressor at all times so asto prevent damage to the compressor from overheating or the like.Inasmuch as modern compressors rely upon the circulation of refrigerantthrough the compressor for supplying lubrication to the compressor, itis also important, from the lubricating standpoint, to circulate acertain minimum amount of refrigerant through the compressor at alltimes when the compressor is in operation.

The reference numeral 40 designates any conventional compressoroperating means such as an internal combustion engine or an electricmotor. As shown in the drawing, the compressor operating means 40 alsooperates the condenser fan 4|.-

In order to simplify this disclosure, no control means have been shownfor controlling the operation of the compressor operating means 40 asany conventional control means may be employed. By virtue ofthe improvedarrangement of the refrigerating system, the compressor operating meansmay be operated continuously at a high -when refrigerant is not beingsupplied to the evaporator without injury to the compressor mechanism,the system is also well adapted for use with a. continuously runningdirect-connected electric motor.

'For purposes of illustration we have shown a system in which therefrigerant flowing through the by-pass valve 30 is evaporated byflowing through the heat interchanger 1, whereas it is within th purviewof this invention to evaporate this refrigerant by other means. When anin-' ternal combustion engine is used for operating the valve 3|) isequal to the amount which must the compressor, the exhaustgas or the hotengine jacket water could be used in evaporating the refrigerant flowingthrough the by-pass. The by-passed refrigerant could also be used indoing useful cooling such as freezing ice, cooling air or the like. r

The valve 30 which is arranged in the bypass line may, if desired, beadjusted so as to allow a predetermined amount of refrigerant to leakthrough the by-pass line even though the suction pressure is abovethe-value at which the valve 30 moves to its fully open position.Leakage through the by-pass around the evaporator reduces the capacityof the evaporator whereby the valve 26 opens and closes less frequently.This causes smoother operation of the refrigerating system and, to agreat extent, prevents frequent temperature fluctuations within theconditioned space. While the form of embodiment of the invention asherein disclosed, constitutes a preferred form, it is to be understoodthat other forms might be adopted, all coming within the scope.

of the claims which follow.

What is claimed is as follows:

1. In combination, a compressor, a continuously running internalcombustion engine for operating said compressor, a first evaporator, asecond evaporator, a condenser, means for conveying liquid refrigerantfrom said condenser into thermal exchange with said compressor and aprime mover for driving said shaft, a condenser, an evaporator, a shaftseal cooling cavity, refrigerant flow connections between saidevaporator, compressor, condenser and shaft seal cooling cavity, meansfor by-passing said evaporator, means for vaporizing refrigerant flowingthrough said by-pass, and means responsive to the suction pressure ofsaid compressor for conv frigerant flow connections between saidevaporator, compressor, .aeondenser and compressor cooling cavity,valve'means for preventing the flow of refrigerant to said evaporator,said refrigerant flow connections and said condenser being soconstructed and arranged as to supply refrigerant tosaid compressorcooling cavity when said valve means prevents the flow of refrigerant tosaid evaporator and also when said valve means permits the flow ofrefrigerant to said evaporator.

4. In combination, a first evaporator, a second evaporator, refrigerantliquefying means including a condenser portion, means for conveyingliquid refrigerant from said condenser portion into thermal exchangerelationship with another portion of said refrigerant liquefying meansand thereafter in thermal exchange relationship with refrigerant leavingeither one of said evaporators so as to recondense the refrigerantvaporized while in thermal exchange relationship with said otherportion, and means a for thereafter conveying said recondensedrefrigerant to one 'refrigerant flowing to either said by-fiass or saidevaporator in thermal exchange with said compressor, valvemeanscontrolling the fiow of refrigerant to said evaporator, valve meanscontrolling the flow of refrigerant through said bypass, and means forconveying refrigerant flowing through said by-pass in thermal exchangewith refrigerant flowing from said compressor to said condenser.

6. In combination, a motor-compressor unit, a, first evaporator, asecond evaporator, a condenser, means for conveying liquid refrigerantfrom said condenser into thermal exchange re- -lationship with a portionof said motorwompressor unit and thereafter into thermal exchangerelationship with refrigerant vapor leaving one of said evaporators soas to recondense the refrigerant vaporized in thermal exchange with saidcompressor.

7. In combination, a compressor, means for operating said" compressor, afirst evaporator, a second evaporator, a condenser, means for con-'veying liquid refrigerant from said condenser into thermal exchange withsaid compressor and I momma E. GOULD. onanws n. HENNEY.

